makefile: find a position of word in a variable

Question

In my makefile, I need to make a variable assignment based on a command line variable value. for example, I do:

make var_1=xxx

where

Answer 1

It's a little kludgey, but if there's a symbol you know won't be in any of the values (such as "_") you could do this:

var_1_values = a b c d
var_2_values = A B C D

# This will be a_A b_B c_C d_D
LIST1 = $(join $(addsuffix _,$(var_1_values)),$(var_2_values))

var_1 := a

# The filter gives a_A, the subst turns it into A
var_2 = $(subst $(var_1)_,,$(filter $(var_1)_%, $(LIST1)))